This invention relates to apparatus and a method for connecting a pin array and a circuit board. In particular the invention relates to pin array connections used in connecting disk drive pin array connectors into disk drive circuit board enclosures.
Disk drive pin array connectors are characterized in that they need to be plugged into and out of the enclosure without necessarily having power to the enclosure or power to the drive turned off. For instance, the drive may be one of many drives and it would be undesirable to power them all down just to remove one drive. In this respect it is desirable that the drives are hot pluggable and electrical damage caused by such action is minimized.
One method of preventing electrical damage to the disk or enclosure when removing or inserting the disk is to have some of the connections break or make before others, for instance having the live connections break before the ground connection when removing the plug or having it make after the ground connection when inserting the connection. This can be achieved by arranging the gap between the live connection points so that it is greater than the other connection points.
For instance, mobile phones have wire connection contacts for connecting the phone into a car hands-free phone mount with a power supply. The wire connection contacts in the phone are mounted on a carrier and one wire connection contact is raised higher than the others. The corresponding contacts in the phone mount are leaf spring contacts. When the phone is inserted into the phone mount the raised contact makes first connection upon insertion and breaks last connection upon release. The provision of a carrier with a raised contact allows sequential making and breaking of contacts. The wire connection contact carrier is a single component which is soldered to the circuit board along with the other components. This wire connection carrier only has one level of raised contacts. Furthermore the contacts in the carrier are arranged in a single line of a plurality (e.g., seven) of contacts, each about 4 mm long and just over 1 mm apart.
Another design uses surface mount connectors but surface mount connectors do not perform very well under sideways forces as the solder joints can fail within the solder or lift the copper lands on the board.
In a disk drive a connector typically has more than twenty contacts for connection with the enclosure and requires a positive and firm connection.
U.S. Pat. No. 5,447,442 discloses a connector pin array which may be used for multiple firm connections. Each of the pins is individually sprung so that it is independently movable and makes a firm electrical connection with its contact point. The socket housing comprises passageways for receiving the pins and making a connection.
The prior art comprises components for making a firm connection which allows for sequential making and breaking of the contacts but there is room for improvement in the areas of simplicity, cost, flexibility of design and reliability of connection.
It is a primary object of the invention to enhance the art of arrayed pin connections.
It is another object of the invention to provide an enhanced connection of this type between a pin array and a printed circuit board.
An even further object is to provide such an improved connection for use in connecting disk drives and the like.
According to one aspect of the invention, there is provided a plug connector for electrically connecting a first PCB to a second PCB having at least two different conductive layers therein at different levels, the plug connector electrically connected to the first PCB and comprising a plug housing adapted for being positioned on the second PCB, a pin carrier movably positioned within the plug housing while the plug housing is positioned on the second PCB, at least two pin mechanisms positioned within the pin carrier, each including a conductive pin movably positioned within the pin carrier and extending therefrom, a first of the conductive pins engaging a corresponding one of the conductive layers in the second PCB, and the second conductive pin engaging another of the conductive layers in the second PCB after the first pin engagement with the first conductive layer in response to the movement of the pin carrier within the plug housing.
According to another aspect of the invention, there is provided a method of electrically connecting a first PCB to a second PCB having at least two different conductive layers therein at different levels within the second PCB, the method comprising electrically coupling a plug connector at one end thereof to the first PCB, positioning a plug housing of the plug connector on the second board, the plug connector further including a pin carrier and at least two pin mechanisms positioned within the pin carrier and including a pin as part thereof, moving the pin carrier within the plug housing to cause a first of the pins of one of the pin mechanisms to engage a first conductive layer within the second PCB, and thereafter further moving the pin carrier within the plug housing to cause a second of the pins of the other of the pin mechanisms to engage a second conductive layer at a different level within the second PCB after the first pin has engaged the first conductive layer.
By replacing the standard connector plugging system with variable depth contacts manufactured directly on the circuit board the cost of connecting disk drives to the enclosure is reduced. At the same time the robustness of the interconnection between removable disk files and multiple stacking systems is maintained. The thickness variation is utilized to maintain the plugging sequence to allow hot plugging of the devices.
The preferred embodiment of invention reduces the manufacturing tolerances of the mating parts and also eliminates any sideways stresses induced into the connection due to misalignment. Conventional connectors typically require precise alignment of the two matting halves, whereas this invention allows for greater tolerances of connector to board displacement because the electrical connection is always equally good, irrespective of misalignment.
Contact positions on the back board can be optimized as these are not dictated by the connector design, which allows better card design and more efficient board layout so high-speed signals and ground returns can be routed for best electrical performance.
In summary, the preferred embodiment of the invention has the following advantages. It allows space for further product enhancements. It reduces costs in a very competitive section of the market. It removes detrimental sideways stresses in the standard connector system and applies the force in the direction of the contact. It removes a card assembly process of the high density connector required for each docking position.